Small Buffer Optimization for string and friends

[Andrei Alexandrescu]

On 4/8/12 1:16 PM, Michel Fortin wrote:
> On 2012-04-08 17:14:37 +0000, Andrei Alexandrescu
> <SeeWebsiteForEmail at erdani.org> said:
>> As I mentioned, the first call to .ptr changes representation, thus
>> making the allocation that the optimization had saved. Things are not
>> worse off than before.
>
> This only works if the code has write access to that variable.
>
> Also, if the variable is a temporary copy such as a by-value function
> parameter, only the representation of that temporary copy will be
> affected. Every time you call a function which calls .ptr a new copy
> will be allocated on the heap. If such a function call is part of a
> loop, it'll degrade performance noticeably.

I think there's a bit of a confusion. Could you please clarify with an 
example?

Thanks,

Andrei